Sun Na, Cui Pengbo, Jin Ziqi, Wu Haitao, Wang Yixing, Lin Songyi
School of Food Science and Technology, Dalian Polytechnic University, National Engineering Research Center of Seafood, Dalian 116034, PR China.
School of Food Science and Technology, Dalian Polytechnic University, National Engineering Research Center of Seafood, Dalian 116034, PR China.
Food Chem. 2017 Sep 1;230:627-636. doi: 10.1016/j.foodchem.2017.03.077. Epub 2017 Mar 14.
This study investigated the contributions of molecular size, charge distribution and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates (SCOHs), and further explored their iron-binding sites. It was demonstrated that enzyme type and degree of hydrolysis (DH) significantly influenced the iron-binding capacity of the SCOHs. The SCOHs produced by alcalase at a DH of 25.9% possessed the highest iron-binding capacity at 92.1%. As the hydrolysis time increased, the molecular size of the SCOHs decreased, the negative charges increased, and the hydrophilic amino acids were exposed to the surface, facilitating iron binding. Furthermore, the Fourier transform infrared spectra, combined with amino acid composition analysis, revealed that iron bound to the SCOHs primarily through interactions with carboxyl oxygen of Asp, guanidine nitrogen of Arg or nitrogen atoms in imidazole group of His. The formed SCOHs-iron complexes exhibited a fold and crystal structure with spherical particles.
本研究调查了分子大小、电荷分布和特定氨基酸对海参（刺参）卵水解物（SCOHs）铁结合能力的贡献，并进一步探索了它们的铁结合位点。结果表明，酶类型和水解度（DH）显著影响SCOHs的铁结合能力。在水解度为25.9%时由碱性蛋白酶产生的SCOHs具有最高的铁结合能力，为92.1%。随着水解时间的增加，SCOHs的分子大小减小，负电荷增加，亲水性氨基酸暴露于表面，有利于铁的结合。此外，傅里叶变换红外光谱结合氨基酸组成分析表明，铁主要通过与天冬氨酸的羧基氧、精氨酸的胍基氮或组氨酸咪唑基团中的氮原子相互作用而与SCOHs结合。形成的SCOHs-铁复合物呈现出具有球形颗粒的褶皱和晶体结构。
